Measurement Formats in ODTK

There are a number of measurement formats supported by ODTK, and each one supports various sets of measurements. Depending on the file type, some measurements may be provided individually, such as range only, while other measurements must be paired, such as azimuth and elevation.

Measurement Formats
Format Type Source Use Measurements Supported
2SOPS binary Air Force Space Command 2nd Space Operation Squadron RAW GPS tracking data. See Format for 2SOPS tracking data(.2SOPS). Ground GPS data to support OD for GPS Constellation

(in raw form):

  • P1 Pseudo-range
  • P2 Pseudo-range

Measurements from different GPS satellites at a given time can be combined to create other measurements:

  • DF Pseudo-range (dual frequency, combines P1 and P2)
  • SD DF Pseudo-range
ACTRAC text ACTRAC format originated with Northrup Grumman's ACTRAC OD package. launch tracking
  • Range
  • Doppler
  • Azimuth/Elevation (pair)
B3 text Air Force Space Command Document AFSPC 160-102, 11 March 1996. See the Tracking Data Formats for the approximation to that format. space surveillance
  • Range
  • Doppler
  • Azimuth/Elevation (pair)
  • Right Ascension/Declination (pair)
  • Space Based Az/El
  • Space Based RA/DEC
  • Space Based Range
CCSDS TDM text Consultative Committee for Space Data Systems (CCSDS) Tracking Data Message, based on RECOMMENDED STANDARD CCSDS 503.0-B-1, available at http://public.ccsds.org/publications/archive/ generic tracking data The following types are implemented by ODTK as of version 6.1.0:
  • Range
  • Doppler*
  • DSN Doppler**
  • Azimuth
  • Elevation
  • Right Ascension
  • Declination
  • 1W Bistatic Range
  • X/Y Angles
Notes: Doppler measurements are formed based on the type of record in the TDM file:

* DOPPLER_INTEGRATED

** RECEIVE_FREQ (specify zero-shifted downlink frequency using either FREQ_OFFSET or TRANSMIT_FREQ, TURNAROUND_NUMERATOR and TURNAROUND_DENOMINATOR)

Notes on Doppler measurements: The TDM format allows for a distinction between integrated and instantaneous Doppler measurements. Integrated Doppler measurements are computed over a time interval specified by the TDM keyword INTEGRATION_INTERVAL. If the INTEGRATION_INTERVAL keyword is not specified, integrated Doppler measurements will be processed using the CountInterval from the tracking facility measurement statistics. The TDM format also allows the time tag for integrated Doppler measurements to be at the END, MIDDLE or START of the integration interval via the INTEGRATION_REF keyword. The ODTK Doppler model, however, assumes that the time tag is at the END. Therefore, if MIDDLE or START is specified, the TDM reader will move the time tag of the measurement to the end time of the integration interval to allow proper processing of the data. The ODTK Doppler model operates on a non-zero integration interval. If instantaneous Doppler measurements are specified, the CountInterval from the tracking facility measurement statistics will be used in processing the data.

Notes on received frequency measurements: Measurements specified using the RECEIVE_FREQ keyword will be interpreted as DSN Doppler or DSN 3W Doppler measurements depending on if the receive site and transmit site are the same. DSN Doppler measurements are computed over a time interval specified by the TDM keyword INTEGRATION_INTERVAL. If the INTEGRATION_INTERVAL keyword is not specified, DSN Doppler measurements will be processed using the CountInterval from the tracking facility measurement statistics. The TDM format also allows the time tag for integrated Doppler measurements to be at the END, MIDDLE or START of the integration interval via the INTEGRATION_REF keyword. The ODTK DSN Doppler model, however, assumes that the time tag is at the MIDDLE. Therefore, if END or START is specified, the TDM reader will move the time tag of the measurement to the middle of the integration interval to allow proper processing of the data.

The CDSDS TDM reader supports XML formatted TDM files and the specific updates required for the TDRSS measurement models.

COB text Air Force Satellite Control Network AFSCN tracking
  • Range
  • Doppler
  • Azimuth
  • Elevation
CRD text

Consolidated Laser Ranging Data Format (CRD)

Version 1.00

R.L. Ricklefs, The University of Texas at Austin/Center for Space Research

C.J. Moore, EOS Space Systems Pty Ltd. For the ILRS Data Formats and Procedures Working Group

http://ilrs.gsfc.nasa.gov/data_and_products/formats/crd.html

Laser ranging
  • Range
  • Azimuth/Elevation (pair)
Notes:
  1. Normal points can be used if read as "NPRange".
  2. CRD Transponder 1-way Range and 2-way Range are not currently supported.
DSN TRK 2-34 binary NASA/JPL Deep Space Network tracking data format TRK-2-34. Documented in: 820-013 Deep Space Mission System (DSMS) External Interface Specification JPL D-16765. Deep space tracking
  • 2 way Sequential Range
  • 2 way Total Count Phase
  • 3 way Total Count Phase
  • 2 way Doppler
  • 3 way Doppler
  • Azimuth/Elevation
  • X/Y Angles
  • DOR
  • QDOR
  • Delta DOR
Ephemeris text See STK Ephemeris file format (*.e)

Note: When using *.e files as measurements the file must be named *\TrkId(nnnn)*.e where nnnn is the TrackingId associated with the associated satellite.
analysis
  • Eph Pos
  • Eph Vel
Generic binary AGI for ODTK stores any measurement in common internal format Everything in ODTK
GEOLOC text Format for Geolocation Tracking Data File (.geoloc) Geolocation Data
  • Ground based TDOA, TDOA Dot and FDOA
  • Ground based singly differenced TDOA and FDOA
  • Space based TDOA, TDOA Dot, FDOA, and FDOA Dot
GEOSC text See the AGI extension of the generic GEOSC format. multiple civilian programs (as used in ODTK):
  • Range
  • Doppler
  • Azimuth/Elevation (pair)
  • Right Ascension/Declination (pair)
  • Space-based Right Ascension/Declination (pair)
  • Space-based Range

NOTE: Support of Space-based Right Ascension/Declination is added by ODTK; native GEOSC does not support space-based angles or range.

NOTE: The GEOSC format has been extended to allow the specification of the True Equator Mean Equinox of Date (TEME) reference frame as the coordinate system for RA/Dec measurements. The reference frame is specified by putting a 2 in column 34 and a 3 in column 35 of the ground based RA/Dec record (type 10) and or the space based RA/Dec record (type 12). If the coordinate system is set in the GEOSC record, it cannot be overriden from the ODTK Object Properties window.

ILRS text International Laser Ranging Service's Fullrate format version 2 (formerly MERIT II), as specified in the Tracking Data Formats section. laser ranging
  • Range
  • Azimuth/Elevation (pair)

Note: Normal points can be used if read as "NPRange".

ITC Ephemeris text JSpOC SP ephemeris (*.itc) format.

Note: The trackingID is taken to be the SSC Number on the *.itc.

analysis .Eph Pos
.Eph Vel
NAVSOL text AGI for ODTK GPS Data Single and dual frequency GPS navigation solutions
RINEX text

See ftp://ftp.unibe.ch/aiub/rinex/rnx_leo.txt and GNSS Measurement Types.

GNSS data

ODTK supports the following RINEX versions:

 

RINEX 2.10

RINEX 2.11

RINEX 2.12 (QZSS extension)

RINEX 2.20

RINEX 3.01 (QZSS extension)

RINEX 3.02

 

RINEX format definitions can be found at:

http://igscb.jpl.nasa.gov/components/formats.html

 

QZSS extensions can be found at:

http://qz-vision.jaxa.jp/USE/is-qzss/index_e.html

 

For input, ODTK recognizes and determines processing from the version number in the RINEX Observation file header.

 

For output, ODTK uses the version specified in RINEX Measurement Plugin Config parameter.

 

Edit->Preferences->Plugins->Config->Output Version Parameter

 

Alternatively one can set the windows environmental variable “AGI_ODTK_RINEX2_FORMAT”. For example:

AGI_ODTK_RINEX2_FORMAT=2.12
UTDF binary NASA's Tracking and Acquisition Handbook for the STDN (450-TAH-STDN), October 1994 various civilian programs (as used in ODTK):
  • Range
  • Doppler
  • Azimuth/Elevation
  • X/Y Angles
  • 1W Bistatic Range and Doppler
  • TDRS 4L Range
  • TDRS 3L and 5L Doppler
  • BRTS Range and Doppler

Note: Measurement times are represented by the year followed by the number of seconds into the year in UTC. By convention, the computation of the number of seconds into year ignores the existence of leap seconds occuring between the beginning of the year and the time of the measurement.

Troposphere & Ionosphere delay settings

Some formats such as the GEOSC format include flags to indicate whether or not the data has been corrected (for processing purposes). In other words, if whoever generated the tracking data file has already removed the effects of troposphere or ionosphere, they would set the flag indicating the measurements have been corrected.

Our generic simulation format also keeps track of these flags. From a simulation point of view, if troposphere or ionosphere is not included for a measurement, the flag is set to indicate the measurements have been corrected, or that the measurements do not contain unmodeled biases. If troposphere or ionosphere is enabled, then the flags are set indicating that the measurements do contain those effects.

When the filter processes measurements, if the tracking data flags are set to indicate that ionosphere or troposphere have already been corrected for, then the user settings for modeling those effects are ignored. However, if the tracking data does contain unmodeled biases, the user needs to make sure they model those effects if desired. Thus they have the choice to model or not model troposphere.

The exception to this discussion are the GPS CA, P1 and P2 pseudorange and phase measurements - the modeling of these effects is controlled entirely by user settings.

In the GEOSC format, a flag value of 0 means the data has been corrected and a value of 1 means the data contains the effects of troposphere/ionosphere. The flags appear in columns 33 for ionospheric correction and 34 for tropospheric correction.

If you want to simulate measurements and then be able to toggle on/off troposphere modeling and see the effects in the residuals, then simulate measurements with troposphere enabled, producing a flag of 1 in the tracking data file. Then when filtering, you can toggle the troposphere enabled flag and see the effects in the residuals.

Tracking IDs

Satellite, facility, and receiver tracking ids are nominally connected to ODTK by matching the integer tracking ids contained within the measurement records to the tracking id parameter in the scenario satellite, facility, receiver objects. There are a couple of exceptions:

  1. The CCSDS TDM format uses alphanumeric ids to identify the tracking objects. AliasMapping is required to correlate the alphanumeric tracking id to the integer tracking id in the applicable objects. Reference the MeasurementProcessing -> TrackingIDAlias property in the object white panels. Also reference the Tracking ID Alias.


  2. When processing STK Ephemeris as measurements the satellite id is derived from the data set name, where the data set name must be of the form *TRKID(nnnn)*.e where nnnn is the (1 to 9 digit) tracking id. Reference LaunchPad->Resources->Handy References->Processing STK Ephemeris Data as Measurements.


  3. When processing RINEX measurements the optional MARKER NUMBER record in the header record nominally defines the receiver id. However, if the MARKER NUMBER record is not present, then the receiver id is derived from the data set name which is of the form SATnnnn_* where nnnn is the (1 to 9 digit) receiver id. Reference LaunchPad->Resources->Handy References->Processing GPS Data.

Tracking Data Formats

B3 OBS Formats in ODTK (v4.1 and above)

The official Air Force B3 OBS archive format has not been provided to AGI; however we have assembled a B3 format that should be close, based on several unofficial sources and a lot of staring at historical data sets. Note that this format is the archive format, not the transmission format as sent by various sensors in the Space Surveillance Network. If you aren't sure which type of B3 observations you have, examine the first two characters of each line. If they are "))" (without quotes), then you have transmit B3 observations.

B3 OBS Types in ODTK:

Type Data Items used in ODTK
0 Range rate only
1 Azimuth & elevation
2 Range, azimuth, & elevation
3 Range, azimuth, elevation, & range rate
4 Range, azimuth, elevation, & range rate (extra measurements for azimuth rate, elevation rate, etc are ignored)
5 Right Ascension & Declination
6 Range only
8 Space-based azimuth, elevation, sometimes range and EFG position of the sensor
9 Space-based right ascension, declination, sometimes range and EFG position of the sensor

For all types the following format applies. If an OBS type does not include a specific measurand, then those columns are blank.

Columns Description
1 Security classification. Typically "U" = unclassified. May be other characters as well.
2-6 SSSSS = Integer satellite ID corresponding to the SSC number.
7-9 sss = Integer sensor ID
10-11 YY = year (assumes 20YY if YY ≤ 50, 19YY if YY > 50)
12-14 DDD = day of year where 1 Jan is considered to be day 1.
15-23 HHMMSSSSS, hour, min, seconds, where implied decimal is SS.SSS (or think of SSSSS as the number of milliseconds).
24-29 EEEEEE = Either the elevation or declination value in degrees, with implied decimal EE.EEEE. Negative elevation / declination values are formatted as overpunched [1] values.
30 Blank. Most likely a remnant of the weighting flag used in the transmit B3 format.
31-37 AAAAAAA = Azimuth or Right Ascension. Azimuth is in degrees with implied decimal AAA.AAAA and is always positive. Right Ascension is in HHMMSSS, with implied decimal in SS.S.
38 Blank. Most likely a remnant of the weighting flag used in the transmit B3 format.
39-45 RRRRRRR = Range in km RR.RRRRR*10^E. Note that types 8 and 9 commonly do not have a range value and these columns will be set to "0000000".
46 E = Range exponent (0 < E < 5). Types 8 and 9 will leave this blank if the range value is "0000000".
47-73 Observation type specific. See the sections below.
74 Blank.
75 Obs type
76 Equinox indicator which specifies the inertial frame for optical observations (Types 5 and 9 only). If used:

0 - True Equator Mean Equinox of Date
1 - Mean Equator Mean Equinox of Jan 0
2 - Mean Equator Mean Equinox of J2000
3 - Mean Equator Mean Equinox of B1950
If the observation record is only 75 bytes long or if column 76 contains a space character, the optical frame specified in the associated tracking object in ODTK will be used.

For types other than 8 or 9 columns 47-73 are defined using the format:

Columns Description
47 Blank. Most likely a remnant of the weighting flag used in the transmit B3 format.
48-54 rrrrrrr = slant range rate (km/s), with implied decimal rr.rrrrr. For negative range rate, the first digit will be a "-" character and you'll have one less digit of precision.
55-73 Blank.

For types 8 and 9 columns 47-73 are defined using the format:

Columns Description
47-55 XXXXXXXXX = X/Y/Z X component of sensor position in meters, column 47 is reserved for the sign, decimal implied after column 55
56-64 XXXXXXXXX = X/Y/Z Y component of sensor position in meters, column 56 is reserved for the sign, decimal implied after column 64
65-73 XXXXXXXXX = X/Y/Z Z component of sensor position in meters, column 65 is reserved for the sign, decimal implied after column 73

EFG coordinates are pseudo-body-fixed coordinates which differ from Earth-Fixed coordinates by the effect of polar motion. These coordinates are sometimes referred to as True of Date Rotating (TDR) coordinates.

Overpunched values are remnants of the days when data was stored on 80-column cards. To indicate that a value is negative you would normally place a negative sign "-" character in front of it. When using fixed format values this would cause you to lose a digit of precision. So instead you simply "overpunched" the first digit. See http://en.wikipedia.org/wiki/Punch_card for details. The end result is the translation J = -1, K = -2, ..., R = -9.

Geolocation Tracking Data File (.geoloc)

Format for Geolocation Tracking Data File

Each line contains a single record. Each record begins with the following standard information (space delimited):

RecordType   Year   Month   Day   Hour   Minute   Seconds   TimeScale
Field Description Type
RecordType Identifies content of data to follow Integer
Year 4 digit year Integer
Month 2 digit month, Jan = 01 Integer
Day 2 digit day of month Integer
Hour 2 digit hour of day Integer
Minute 2 digit minute of hour Integer
Seconds Seconds Real
TimeScale 0 - UTC, 1 - GPS Integer

RecordType = 0 is used to describe ground-based TDOA and FDOA measurements (computed as path 2 minus path 1) and has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S1XID Identifier for satellite 1 transponder (-1 indicates not supplied) Integer
S1XDelay Delay (ns) for satellite 1 transponder (-1 indicates not supplied) Real
S1XTrans Additive freq translation in Hz for sat 1 transponder (0 indicates not supplied) Real
S2ID Tracking identifier for satellite 2 Integer
S2XID Identifier for satellite 2 transponder (-1 indicates not supplied) Integer
S2XDelay Delay (ns) for satellite 2 transponder (-1 indicates not supplied) Real
S2XTrans Additive freq translation in Hz for sat 2 transponder (0 indicates not supplied) Real
RID Tracking identifier for receive station Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid FDOA measurement (1 - valid, 0 - invalid) Integer
FDOA Freq difference of arrival (path 2 - path 1) in Hz Real
SigmaFDOA White noise uncertainty in FDOA in Hz (0 indicates not specified) Real

RecordType = 1 is used to describe ground-based TDOA and TDOA Dot measurements (computed as path 2 minus path 1) and has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S1XID Identifier for satellite 1 transponder (-1 indicates not supplied) Integer
S1XDelay Delay (ns) for satellite 1 transponder (-1 indicates not supplied) Real
S1XTrans Additive freq translation in Hz for sat 1 transponder (0 indicates not supplied) Real
S2ID Tracking identifier for satellite 2 Integer
S2XID Identifier for satellite 2 transponder (-1 indicates not supplied) Integer
S2XDelay Delay (ns) for satellite 2 transponder (-1 indicates not supplied) Real
S2XTrans Additive freq translation in Hz for sat 2 transponder (0 indicates not supplied) Real
RID Tracking identifier for receive station Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
TDOA Dot Validity Indicator of a valid TDOA Dot measurement (1 - valid, 0 - invalid) Integer
TDOA Dot Time derivative of TDOA (path 2 - path 1) (unitless) Real
SigmaTDOADot White noise uncertainty in TDOA Dot (unitless) (0 indicates not specified) Real

RecordType = 2 is used to describe ground-based singly-differenced TDOA and FDOA (computed as emitter 2 minus emitter 1, each DOA is path 2 minus path 1):

Field Description Type
EID1 Tracking identifier for the emitter Integer
EFreq1 Frequency of transmission from emitter 1 in Hz (-1 indicates not supplied) Real
EID2 Tracking identifier for the emitter 2 Integer
EFreq2 Frequency of transmission from emitter 2 in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S1X1ID Identifier for satellite 1 transponder used with emitter 1 (-1 indicates not supplied) Integer
S1X1Delay Delay (ns) for satellite 1 transponder used with emitter 1 (-1 indicates not supplied) Real
S1X1Trans Additive frequency translation in Hz for sat 1 transponder used with emitter 1 (0 indicates not supplied) Real
S1X2ID Identifier for satellite 1 transponder used with emitter 2 (-1 indicates not supplied) Integer
S1X2Delay Delay (ns) for satellite 1 transponder used with emitter 2 (-1 indicates not supplied) Real
S1X2Trans Additive frequency translation in Hz for sat 1 transponder used with emitter 2 (0 indicates not supplied) Real
S2ID Tracking identifier for satellite 2 Integer
S2X1ID Identifier for satellite 2 transponder used with emitter 1 (-1 indicates not supplied) Integer
S2X1Delay Delay (ns) for satellite 2 transponder used with emitter 1 (-1 indicates not supplied) Real
S2X1Trans Additive frequency translation in Hz for satellite 2 transponder used with emitter 1 (0 indicates not supplied) Real
S2X2ID Identifier for satellite 2 transponder used with emitter 2 (-1 indicates not supplied) Integer
S2X2Delay Delay (ns) for satellite 2 transponder used with emitter 2 (-1 indicates not supplied) Real
S2X2Trans Additive frequency translation in Hz for satellite 2 transponder used with emitter 2 (0 indicates not supplied) Real
RID Tracking identifier for receive station Integer
TDOAValidity Indicator of a valid SD TDOA measurement (1 - valid, 0 - invalid) Integer
SDTDOA Singly differenced (emitter2 - emitter1) time difference of arrival (path 2 - path 1) in seconds Real
SigmaSDTDOA White noise uncertainty in SD TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid SD FDOA measurement (1 - valid, 0 - invalid) Integer
SDFDOA Singly differenced (emitter2 - emitter1) freq difference of arrival (path 2 - path 1) in Hz Real
SigmaSDFDOA White noise uncertainty in SD FDOA in Hz (0 indicates not specified) Real

RecordType = 3 is used to describe space based TDOA and FDOA measurements (computed as path 2 minus path 1) and has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S2ID Tracking identifier for satellite 2 Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid FDOA measurement (1 - valid, 0 - invalid) Integer
FDOA Freq difference of arrival (path 2 - path 1) in Hz Real
SigmaFDOA White noise uncertainty in FDOA in Hz (0 indicates not specified) Real

RecordType = 4 is used to describe space based TDOA and TDOA Dot measurements (computed as path 2 minus path 1) and has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S2ID Tracking identifier for satellite 2 Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
TDOA Dot Validity Indicator of a valid TDOA Dot measurement (1 - valid, 0 - invalid) Integer
TDOA Dot Time derivative of TDOA (path 2 - path 1) (unitless) Real
SigmaTDOADot White noise uncertainty in TDOA Dot (0 indicates not specified) (unitless) Real

RecordType = 5 is used to describe TDOA and FDOA measurements from a space based emitter to two ground stations (computed as path 2 minus path 1) and has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
R1ID Tracking identifier for receive station 1 Integer
R2ID Tracking identifier for receive station 2 Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid FDOA measurement (1 - valid, 0 - invalid) Integer
FDOA Freq difference of arrival (path 2 - path 1) in Hz Real
SigmaFDOA White noise uncertainty in FDOA in Hz (0 indicates not specified) Real

RecordType = 6 is used to describe TDOA, FDOA and FDOA Dot measurements from a space based emitter to two ground stations (computed as path 2 minus path 1) and has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
R1ID Tracking identifier for receive station 1 Integer
R2ID Tracking identifier for receive station 2 Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid FDOA measurement (1 - valid, 0 - invalid) Integer
FDOA Freq difference of arrival (path 2 - path 1) in Hz Real
SigmaFDOA White noise uncertainty in FDOA in Hz (0 indicates not specified) Real
FDOADotValidity Indicator of a valid FDOA Dot measurement (1 - valid, 0 - invalid) Integer
FDOADot Freq difference of arrival rate (path 2 - path 1) in Hz/sec Real
SigmaFDOADot White noise uncertainty in FDOA Dot in Hz/sec (0 indicates not specified) Real

RecordType = 7 is used to describe TDOA and TDOA Dot measurements (computed as path 2 minus path 1) where signals from two emitters pass through a single satellite to a single ground station and has the following additional space delimited fields:

Field Description Type
E1ID Tracking identifier for emitter 1 Integer
E1Freq Frequency of emitter 1 transmission in Hz (-1 indicates not supplied) Real
E2ID Tracking identifier for emitter 2 Integer
E2Freq Frequency of emitter 2 transmission in Hz (-1 indicates not supplied) Real
SID Tracking identifier for the satellite Integer
RID Tracking identifier for the receive facility Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
TDOA Dot Validity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Dot Time derivative of TDOA (path 2 - path 1) (unitless) Real
SigmaTDOADot White noise uncertainty in TDOA Dot (0 indicates not specified) (unitless) Real

RecordType = 8 is used to describe space based TDOA and FDOA measurements (computed as path 2 minus path 1) where signals from a single space based emitter to two space based receivers. The format of RecordType 8 records is identical to that of RecordType 3.

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S2ID Tracking identifier for satellite 2 Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid FDOA measurement (1 - valid, 0 - invalid) Integer
FDOA Freq difference of arrival (path 2 - path 1) in Hz Real
SigmaFDOA White noise uncertainty in FDOA in Hz (0 indicates not specified) Real

RecordType = 9 is used to describe ground-based TDOA and FDOA measurements (computed as path 2 minus path 1) where the signal paths are emitter-satellite1-receiver1 and emitter-satellite2-receiver2. This record type has the following additional space delimited fields:

Field Description Type
EID Tracking identifier for the emitter Integer
EFreq Frequency of transmission in Hz (-1 indicates not supplied) Real
S1ID Tracking identifier for satellite 1 Integer
S1XID Identifier for satellite 1 transponder (-1 indicates not supplied) Integer
S1XDelay Delay (ns) for satellite 1 transponder (-1 indicates not supplied) Real
S1XTrans Additive freq translation in Hz for sat 1 transponder (0 indicates not supplied) Real
S2ID Tracking identifier for satellite 2 Integer
S2XID Identifier for satellite 2 transponder (-1 indicates not supplied) Integer
S2XDelay Delay (ns) for satellite 2 transponder (-1 indicates not supplied) Real
S2XTrans Additive freq translation in Hz for sat 2 transponder (0 indicates not supplied) Real
R1ID Tracking identifier for receive station 1 Integer
R2ID Tracking identifier for receive station 2 Integer
TDOAValidity Indicator of a valid TDOA measurement (1 - valid, 0 - invalid) Integer
TDOA Time difference of arrival (path 2 - path 1) in seconds Real
SigmaTDOA White noise uncertainty in TDOA in seconds (0 indicates not specified) Real
FDOAValidity Indicator of a valid FDOA measurement (1 - valid, 0 - invalid) Integer
FDOA Freq difference of arrival (path 2 - path 1) in Hz Real
SigmaFDOA White noise uncertainty in FDOA in Hz (0 indicates not specified) Real

Notes:

The transponder delay and transponder frequency translation data is not currently passed to the filter.

Example record (standard information):

RecordType Year Month Day Hour Minute Seconds
0 2006 11 15 00 00 15.0 + type-specific data

Example type-specific data (type 0 information):

EID EFreq S1ID S1XID S1XDelay S1XTrans S2ID S2XID S2XDelay S2XTrans RID TDOAValidity TDOA SigmaTDOA FDOAValidity FDOA SigmaFDOA
101 14321.0e+06 1111 -1 -1 0 2222 -1 -1 0 300 1 0.01254653 0 1 1.65372 0

GEOSC Format for ODTK 5

GEOSC for Space Based RA/DEC

AGI has extended the generic GEOSC format for space based angles data.

Column Description
1-7 Target Satellite ID
8-9 12 = Space Based tracker (AGI extension to format)
10 0 = time tagged at sensor receive time
1,2,3 not valid for SB angles in ODTK
11 3 = UTC time tag
12-16 Not used in ODTK - reserved for GB tracker ID
17-18 YY = year
19-21 DDD = day of year
22-26 SSSSS = time of day in integer seconds
27-32 FFFFFF = fraction of seconds
33 Not used
34 0 = MEME (Col 35 = 1, 2, or 3)
1 = TETE (Col 35 = 2 or 3)
2 = TEME (only with Col 35 = 3)
3 = ICRF (AGI extension to format)
35 0 = not set
1 = B1950.0
2 = Jan 0.0 of observation year
3 = Equinox and equator of date (instant of observation)
4 = J2000 standard equator and equinox
37-38 HH = integer hours for RA
39-40 MM = integer minutes for RA
41-45 SSSSS = SS.SSS = seconds for RA
46 Sign of DEC
47-48 DD = degrees of DEC
49-50 MM = minutes of DEC
51-54 SSSS = SS.SS = seconds of DEC
55 0 = annual aberration correction has been applied
1 = annual aberration correction has not been applied
56 Not used - reserved for parallactic refraction
57 0 = diurnal aberration correction has been applied
1 = diurnal aberration correction has not been applied
58-61 XXXX = standard deviation in RA (XX.XX arcsec)
Zero will result in ODTK using sensor defaults
62-65 XXXX = standard deviation in DEC (XX.XX arcsec)
Zero will result in ODTK using sensor defaults
69-73 Sensor satellite (SBSS, SBV) ID

GEOSC for Range

Column Description
1-7 Target Satellite ID
8-9 21 = Range
10 0 = time tagged at sensor receive time
1 = time tagged at reflection from satellite
2 = time tagged at transmit time
11 3 = UTC time tag
12-16 GB tracker ID
17-18 YY = year
19-21 DDD = day of year
22-26 SSSSS = time of day in integer seconds
27-32 FFFFFF = fraction of seconds
33 Ionospheric correction indicator, default = 0 (corrected)
34 Tropospheric correction indicator, default = 0 (corrected)
35 Not used in ODTK, transponder correction indicator, default = 1 (not corrected)
36-45 Range, integer km
46-54 Range, fraction of km
55 0 = simplified speed of light 2.997925*10^8 m/sec (not used in ODTK)
3 = full speed of light 2.99792458*10^8 m/sec
56 Transponder type not used in ODTK (1 = coherent, assumed in ODTK)
57-61 GB tracker ID (repeated in ODTK)
62-68 Not used in ODTK - reserved for Temp, press, humid
69-73 XXXXX = standard deviation in range (XX.XXX meters)
Zero will result in ODTK using sensor defaults

GEOSC for Range Rate

Column Description
1-7 Target Satellite ID
8-9 34 = Doppler reported as Range Rate
10 0 = time tagged at sensor receive time
1 = time tagged at reflection from satellite
2 = time tagged at transmit time
11 3 = UTC time tag
12-16 GB tracker ID
17-18 YY = year
19-21 DDD = day of year
22-26 SSSSS = time of day in integer seconds
27-32 FFFFFF = fraction of seconds
33 Ionospheric correction indicator, default = 0 (corrected)
34 Tropospheric correction indicator, default = 0 (corrected)
35 Not used in ODTK, type of mount, default = 3 (Az-El)
36-42 Doppler count interval XXXXX.XX sec
43-49 Range rate integer portion in meters/sec
50-55 Range rate fractional portion in meters/sec
56 0 = simplified speed of light 2.997925*10^8 m/sec (not used in ODTK)
3 = full speed of light 2.99792458*10^8 m/sec
57-61 GB tracker ID (repeated in ODTK)
62-68 Not used in ODTK - reserved for Temp, press, humid
69-73 XXXXX = standard deviation in range rate (XXX.XX mm/sec)
Zero will result in ODTK using sensor defaults

GEOSC for Ground-Based azimuth and elevation

Column Description
1-7 Target Satellite ID
8-9 71 = Azimuth / elevation
10 Not used in ODTK, all GB angles treated as time tagged at reflection from satellite
11 3 = UTC time tag
12-16 GB tracker ID
17-18 YY = year
19-21 DDD = day of year
22-26 SSSSS = time of day in integer seconds
27-32 FFFFFF = fraction of seconds
33 Not used in ODTK, ionospheric correction indicator, default = 0 (corrected)
34 Tropospheric correction indicator, default = 0 (corrected)
35 Not used
36-38 AAA = integer degrees of azimuth
39-40 MM = arc minutes of azimuth
41-45 SSSSS = SS.SSS = arc seconds of azimuth
46 Sign of elevation
47-48 DD = degrees of elevation
49-50 MM = minutes of elevation
51-54 SSSS = SS.SS = seconds of elevation
55-57 Not used - reserved for parallactic refraction
58-61 XXXX = standard deviation in azimuth (XX.XX arcminutes)
Zero will result in ODTK using sensor defaults
62-65 XXXX = standard deviation in elevation (XX.XX arcminutes)
Zero will result in ODTK using sensor defaults

GEOSC for Ground-Based RA/DEC

Column Description
1-7 Target Satellite ID
8-9 10 = ground-based tracker
10 0 = time tagged at sensor receive time
1,2,3 not valid for SB angles in ODTK
11 3 = UTC time tag
12-16 Not used in ODTK - reserved for GB radar ID
17-18 YY = year
19-21 DDD = day of year
22-26 SSSSS = time of day in integer seconds
27-32 FFFFFF = fraction of seconds
33 Not used
34 0 = MEME (Col 35 = 1, 2, or 3)
1 = TETE (Col 35 = 2 or 3)
2 = TEME (only with Col 35 = 3)
3 = ICRF (AGI extension to format)
35 0 = not set
1 = B1950.0
2 = Jan 0.0 of observation year
3 = Equinox and equator of date (instant of observation)
4 = J2000 standard equator and equinox
37-38 HH = integer hours for RA
39-40 MM = integer minutes for RA
41-45 SSSSS = SS.SSS = seconds for RA
46 Sign of DEC
47-48 DD = degrees of DEC
49-50 MM = minutes of DEC
51-54 SSSS = SS.SS = seconds of DEC
55 0 = annual aberration correction has been applied
1 = annual aberration correction has not been applied
56 Not used - reserved for parallactic refraction
57 0 = diurnal aberration correction has been applied
1 = diurnal aberration correction has not been applied (not used in ODTK for GB angles trackers)
58-61 XXXX = standard deviation in RA (XX.XX arcsec)
Zero will result in ODTK using sensor defaults
62-65 XXXX = standard deviation in DEC (XX.XX arcsec)
Zero will result in ODTK using sensor defaults
69-73 GB Tracker ID

GEOSC for Ground-Based X/Y angles

Column Description
1-7 Target Satellite ID
8-9 60 = X/Y East-West, 64 = X/Y North-South
10 Not used in ODTK, all GB angles treated as time tagged at reflection from satellite
11 3 = UTC time tag
12-16 GB tracker ID
17-18 YY = year
19-21 DDD = day of year
22-26 SSSSS = time of day in integer seconds
27-32 FFFFFF = fraction of seconds
33 Not used in ODTK, ionospheric correction indicator, default = 0 (corrected)
34 Tropospheric correction indicator, default = 0 (corrected)
35 Not used
36 Sign of X
37-38 AA = integer degrees of X
39-40 MM = arc minutes of X
41-45 SSSSS = SS.SSS = arc seconds of X
46 Sign of Y
47-48 DD = degrees of Y
49-50 MM = minutes of Y
51-54 SSSS = SS.SS = seconds of elevation
55-57 Not used - reserved for parallactic refraction
58-61 XXXX = standard deviation in X (XX.XX arcminutes)
Zero will result in ODTK using sensor defaults
62-65 XXXX = standard deviation in Y (XX.XX arcminutes)
Zero will result in ODTK using sensor defaults

ILRS Fullrate Format (Version 3. Apr 1999)

Modified for ODTK (in red)

(Formerly known as MERIT II)

Bytes Description Example
1-7 ILRS Satellite Identification Number - 7 digit number based on COSPAR ID '7603901'
8-9 Year of Century - 2 digits with leading zero fill '09'
10-12 Day of Year - 3 digits with leading blank fill ' 34'
13-24 Time of Day - from midnight GMT with a .1 microsecond granularity and leading blank fill ' 36005000000'
25-28 Crustal Dynamics Project Pad ID- a 4-digit monument identification '7105'
29-30 Crustal Dynamics Project 2-digit system number '07'
31-32 Crustal Dynamics Project 2-digit occupancy sequence number '24'
33-39 Azimuth - the geometric or true azimuth angle with a .1 millidegree granularity and leading blank fill ' 987500'
40-45 Elevation - the geometric or true elevation angle with a .1 millidegree granularity and leading blank fill '292500'
46-57 Laser Range - in units of two way time with a 1 picosecond granularity and leading blank fill ' 52035998000'
58-64 Pass RMS from the mean of raw range values minus the trend function, for accepted ranges (two-way value in picoseconds). ' 66'
65-68 Wavelength of the laser with leading blank fill
The user of the data should interpret the value given as follows:
3000 - 9999: units are 0.1 nanometer
1000 - 2999: units are 1.0 nanometer
0030 - 0.9999 units are 100 nanometers (0.1 micron)
For the station generating the data, the rule is:
Wavelength in rate 0.3000 - 0.9999 microns: unit 0.1 nanometer
Wavelength in rate 1.000 - 2.999 microns: unit 1.0 nanometer
Wavelength in rate 3.0 - 99.9 microns: unit 100 nanometers (0.1 micron)
'5321'
69-73 Surface Pressure - .1 millibar granularity with leading blank fill '10135'
74-77 Surface Temperature - .1 degree Kelvin granularity with leading blank fill '2905'
78-80 Relative Humidity at Surface - percentage with leading blank fill ' 55'
81-85 Tropospheric refraction correction - a round trip refraction correction with a 1 picosecond granularity and leading blank fill '33956'
86-91 Center of Mass Correction - a round trip correction with a 1 picosecond granularity and leading blank fill ' 1601'
92-96 Receive Amplitude - a positive linear scale value with leading blank fill ' 700'
97-104 Applied System Delay - the two way system delay applied in the current record with a 1 picosecond granularity and leading blank fill '95942'
105-110 Calibration Delay Shift - a measure of two way calibration stability with a 1 picosecond granularity and leading blank fill ' 33'
111-114 Root Mean Square (RMS) of raw system delay values from the mean. Two-way value in picoseconds. If pre- and post- pass calibrations are made, use the mean of the two RMS values, or the RMS of the combined data set ' 40'
115 Normal Point Window Indicator - indicates whether or not the record represents a normal point and the time span of the normal point
0: not a normal point
1: 5-second normal point (GFZ-1)
2: LLR normal point
3: 15-second normal point (TOPEX)
4: 20-second normal point
5: 30-second normal point
6: 1-minute normal point
7: 2-minute normal point (LAGEOS)
8: 3-minute normal point
9: 5-minute normal point (ETALON)
'0'
116-119 Number of raw ranges compressed into normal point leading blank fill ' '
120 Epoch Event - indicates the time event reference.
Currently, only 1 and 2 are used for laser ranging data.
0 = Ground receive time
1 = Satellite transmit time (standard for LAGEOS)
2 = Ground transmit time
3 = Satellite receive time
'1'
121 Epoch Time Scale - indicates the time scale reference.
Other flags may appear for historical data.
3 = UTC (USNO)
4 = UTC (GPS)
7 = UTC (BIH)
'3'
122 Angle Origin Indicator - source of angle values.
0 = Unknown (converted from MERIT I)
1 = Computed (from range)
2 = Command (predicts and operator inputs)
3 = Measured (calibrated instrument readings)
'3'
123 Tropospheric Refraction Correction Indicator
0 = Data has been corrected using the Marini-Murray formula
1 = Data has not been corrected
'0'
124 Center of Mass Correction Application Indicator
0 = Applied
1 = Not applied
'0'
125 Receive Amplitude Correction Indicator
0 = Data has been receive amplitude corrected
1 = Data has not been receive amplitude corrected
'1'
126 System calibration method and delay shift indicator. Indicates the type of calibration and the type of calibration shift given in columns 105-110
Pre- to Post-Pass
Calibration Shift
Minimum to Maximum
Calibration Shift
External cal 0 5
Internal cal 1 6
Burst cal 2 7
Some other cal 3 8
Not used 4 9
'0'
127 System CHange indicator (SCH). A flag to increment for every major change to the system (hardware or software). After the value '9' return to '0', and then continue incrementing. The station and data centers should keep a log in a standard format of the value used, the date of the change, and a description of the change. '0'
128 System Configuration Indicator (SCI). A flag used to indicate alternative modes of operation for a system (e.g., choice of alternative timers or detectors, or use of a different mode of operation for high satellites). Each value of the flag indicates a particular configuration, which is described in a log file held at the station and at the data centers. If only a single configuration is used then use a fixed value. If a new configuration is introduced then use the next higher flag value. If value exceeds '9' then return to '0', overwriting a previous configuration flag (it is not likely that a station will have 10 current possible configurations). '1'
129 Format Revision Number Indicator - indicates the version of the MERIT II format for the current record. Data prior to MERIT II that is converted into the MERIT II format will have a revision number of '0'. '3'
130 Release Flag Indicator - indicates when this record first appeared on a release tape. Cooperating stations which send release tapes to the CDDIS will use a numbering scheme beginning with '1'. Release tapes from the CDDIS will have a labelling scheme beginning with 'A'. Non-operational engineering data will have a release flag of 'Z'. Data released prior to the MERIT II implementation will have a release flag of '0'. 'A'

Specifications on the Fullrate format:

  1. A field should be blank if a value does not apply or if the value is unknown.
  2. All fields should have trailing '0' fill when the accuracy of the field value is less than the accuracy of the format.
  3. The range and all correction fields are in two way time units of picoseconds for both accuracy and consistency.
  4. All correction field values, except the center of mass, are represented such that they would be subtracted from the laser range when applied. The center of mass value is represented such that it would be added to the laser range when applied.
  5. To convert the laser range field from two way time in picoseconds to one way distance in meters:
    1. convert the range in units of picoseconds to seconds
    2. divide the result in a. by 2
    3. multiply the result in b. by the speed of light, (299792458 m/s)

Format for Navigation Solution Tracking Data File (.navsol)

Each line contains a single record. Each record begins with the following standard information (space delimited):

Column Description
ReceiverID Identifier of GPS receiver (integer)
Year 4 digit year (integer)
Month 2 digit month, Jan = 01 (integer)
Day 2 digit day of month (integer)
Hour 2 digit hour of day (integer)
Minute 2 digit minute (integer)
Milliseconds milliseconds into the current minute (real)
DF dual frequency indicator, 1 - dual frequency solution, 0 - single frequency solution
RecordType identifies content of data to follow (integer), valid values are (0,1,2,3). For record types 0 and 2 - time tag interpreted as UTC time. For record types 1 and 3 - time tag interpreted as GPS time.
X X component of navigation solution in Earth Fixed coordinates, meters (real)
Y Y component of navigation solution in Earth Fixed coordinates, meters (real)
Z Z component of navigation solution in Earth Fixed coordinates, meters (real)

RecordTypes = 0 and 1 have the following additional fields

Column Description
Sigma 3D 1 sigma uncertainty for solution, meters (0 indicates not supplied) (real)
NumSVs number of SVs used in navigation solution
PRN# PRN numbers for SVs used in navigation solution

RecordType = 2 and 3 (added in v6.4.2) have the following additional fields

Column Description
Sigma X 1 sigma uncertainty for X component of solution, meters (0 indicates not supplied) (real)
Sigma Y 1 sigma uncertainty for Y component of solution, meters (0 indicates not supplied) (real)
Sigma Z 1 sigma uncertainty for Z component of solution, meters (0 indicates not supplied) (real)
NumSVs number of SVs used in navigation solution
PRN# PRN numbers for SVs used in navigation solution

Notes:

Example record (standard information):

ReceiverID Year Month Day Hour Minute Milliseconds DF RecordType
800 2003 11 15 23 59 47000 0 0 + type-specific data

Example type-specific data (type 0 information):

X Y Z Sigma NumSVs PRN1 PRN2 PRN3 �
4.0465888e+06 -5.6845461e+06 4.5752870e+03 0 8 29 28 13 11 09 08 07 03

Format for 2SOPS GPS Raw Data File (.2sops)

This is a binary file. All multibyte fields are in little endian (least significant byte first) order. Double precision values are IEEE floating point.

Data comes in 6-second chunks from the different Monitor stations. Each record contains data for one of these 6-second chunks. There are 4 pseudo-ranges per record; one pseudo-range per each of 4 successive Z-counts where 1 Z-Count is 1.5 seconds. The first data item - Z-Counts since GPS epoch is the Time of Transmission from the GPS SV. That time corresponds to the last (4th) pseudo-range in the set of 4.

Record Description:

Item Size (bytes) Type Description Units
1 8 Double Time of transmission (t) from GPS SV corresponding to the last (4th) pseudo-range in the set of 4. Z-Counts since GPS Epoch
2 1 Unsigned integer PRN -
3 1 Unsigned integer Monitor Station ID (MSID) -
4 1 Unsigned integer 1 = L1, 2 = L2  
5 1 Unsigned integer Antenna id. = 0 If no antenna id is supplied -
6 4 Unsigned integer Unused -
7 8 Double Pseudo-range 1 meters
8 8 Double Pseudo-range 2 meters
9 8 Double Pseudo-range 3 meters
10 8 Double Pseudo-range 4 meters

ODTK 6.5